Blockchain-Verified Attribute-Based Keyword Search with User-Generated Keys in Multi-owner Setting for IoT

With the rapid advancement of Internet of Things (IoT) technology, the security and utilization of data outsourced to the cloud is a prerequisite for IoT application in actual production. Attribute-based keyword search (ABKS) has emerged as a powerful primitive for fine-grained search over encrypted data for IoT. While recent advanced ABKS schemes support more abundant functions and query structures, they do not consider multi-owner setting. Moreover, these schemes typically rely on a single trusted attribute authority for user certificate verification and private key distribution. This centralization creates a single point of failure and raises security concerns, such as key escrow. Furthermore, the existence of malicious entities necessitates verification mechanisms. However, most existing approaches introduce unvetted third-party validators, leading to reliability issues and privacy risks. Nevertheless, in numerous schemes, malicious entities persist in operational status, thereby compromising systemic security. To address these challenges, we propose ABKS with user-generated keys (ABKS-UGK), which decentralizes key generation to individual data users, fundamentally resolving the key escrow vulnerabilities in traditional schemes. It not only leverages blockchain’s immutability for secure result verification, but also incorporates a revocation mechanism against malicious entities. Extensive experimental evaluations demonstrate its efficiency and reliability, making it suitable for secure, verifiable data sharing in real world.